My first monster fishtank

Hi, new poster here. I have a collection of plecos (common, blue phantom, L240 galaxy, sultan, 3 beacon, bushy) currently spread across two tanks and i want to give them a new massive home. I am looking at getting a 240 gallon and or 190/180 gallon depending on if i need to reinforce the stringers that hold up the floor (i still need to check with an engineer). House has a basement, and my tank will be on ground floor room and back up to an exterior wall. My goal is to maximize the bottom surface area for the tank so as to give each pleco a place to call their own. I am considering 2x Ehime 2081 filters which I hope to store under the tank in the base (iv read they might leak so ill prob keep them in a large Rubbermaid bin). The room the tank is going into has a hardwood floor so I think if i spread the weigh out i should be ok? Based on my math i am looking at between 1800lbs and 2400lbs? My question is am I approaching this correctly? Do i need to consider a sump? I know the plecos are very messy, iv been over filtrating their current tanks and cleaning them weekly. They have perfect water quality. How about water turn over will i have enough with 2 ehimes? Based on my math i should be around 4 times an hour. I will be adding in extra air pumps just in case. Anything else to consider? I have a budget of around 3500 dollars for this project. As a side note, id love to be able to add an L600 some day.
Thanks,
Textile

Well only issue with the floor, is my renter. He lives in a small apartment in my basement. This tank would be right above his bed. Given the fact that i have already had to replace the drop ceiling tiles twice due to my carelessness of refilling my snail breeding tank, i let it overfill a bit and water leaked though, luckily there was no damage to sub-floor as i was able to inspect everything. The ceiling is "finished" but is just a drop ceiling with insulation. I can take it all out and get to the stringers which have a 16" spacing. I really want ensure there is nothing to worry about. I spoke to a good friend of mine who is a contractor and he said something similar though he suggested consulting an engineer. His point was that weights i am looking at are not much different then a full soaker bath tub... Drilled is a good point, i was going to try to avoid that as it jacks the cost up, but since id be saving on filters, it may be a solid bet. Should i just build a sump / filter out of a 75g tank?